This invention relates to a gas control device which is responsive to reaching a predetermined depth, in ambient fluid, for opening a valve controlling a supply of gas. It is of particular utility in, but is not restricted in its use to, providing increase of buoyancy in an underwater buoyancy apparatus.
By way of illustration, it is important that a diver should not exceed the maximum depth to which he intends to dive. However, it is often difficult for a diver to ensure that this intended maximum depth is not exceeded. For example, the underwater visibility may be so limited that the diver cannot read a depth gauge attached to his wrist. Further, the diver may become distacted or have his judgment impaired during diving so that he does not appreciate, or perhaps, care that the intended maximum depth has been exceeded.